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Biomedical subjects

A Miyama

Publications and source records attributed to A Miyama.

67 records · Page 4Linked to original sources
PubMed1979

Complement proteins and macrophages. 1. Quantitative estimation of factor B produced by mouse peritoneal macrophages.

Cobra venom factor was used for the detection of factor B synthesized by mouse peritoneal macrophages. This method was shown to be specific for factor B assay by neutralization by antimouse factor B antibody. The amount of factor B in the culture supernatant, assessed by this method, was found to be dependent on the medium used for cultivation of macrophages. The addition of 25% L cell-conditioned medium to minimal essential medium (LCM-MEM) enhanced the production of factor B and also of lysozyme. Kinetic analysis in LCM-MEM showed that factor B produced by 6 x 10(4) cells/cm2 increased up to 72 hr and reached a plateau at 96 hr. The amounts of factor B and lysozyme produced in LCM-MEM depended upon the number of macrophages. Production of factor B was completely inhibited by 1 microgram of cycloheximide per ml and was restored by its removal.

Animals↗
PubMed1976

Activation of therminal components of human complement by a trypsin-activated complex of human factor B and cobra venom factor.

Cleavage of C3 by CVF-B was demonstrated by hemolytic, immunoelectrophoretic and immune adherence reactions. No cleavage of C5 was detected by immunoelectrophoresis, but C5 hemolytic activity, assayed with EAC1423, decreased although less than C3 hemolytic activity. The co-existence of C3 with limiting amounts of C5 did not reduce the final degree of hemolysis of guinea pig erythrocytes (GPE) induced by late-acting components C6 through C9 and CVF-B. Thus, a CVF-B hemolytic system composed of GPE, C5 through C9 and CVF-B provided a method for titration of terminal components of human complement. CVF-B was able to generate hemolytically active sites of C567 on GPE by activation of C5, C6 and C7. The complex C567 in the fluid-phase decayed within 1 min but C567 on GPE was quite stable. Originally insensitive sheep erythrocytes became sensitive to the CVF-B hemolytic system if C3b sites were present, suggesting that cell-bound C3b played a role in orienting the positions of C567 to be fixed. CVF-B could be recovered quantitatively from the supernatant of the reaction mixture in which the hemolytically active intermediate GPEC-5678 had been formed through the interaction between C5 to C8 and CVF-B.

Animals↗
PubMed1975

Trypsin-activated complex of human factor B with cobra venom factor (CVF), cleaving C3 and C5 and generating a lytic factor for unsensitized guinea pig erythrocytes. I. Generation of the activated complex.

A complex formed between cobra venom factor (CVF) and isolated human factor B (B) was found to be converted by trypsin to a stable enzyme, CVF-B which cleaved the third component (C3) and the fifth component (C5) of human complement. The formation of CVF-B by trypsin required divalent cations, whereas the formation of the lytic factor from human serum occurred even in the presence of EDTA. CVF-B purified by gel filtration could initiate the hemolysis of unsensitized guinea pig erythrocytes when incubated with human complement components C5 to C9 in 0.01 M EDTA buffer. C3 was not required for the lysis of guinea pig erythrocytes initiated by CVF-B because of the beta1C precipitation line formed between human serum and anti-beta1C antibody did not inhibit the hemolysis by CVF-B in agarose gel. Treatment of beta1C and beta1F globulins in whole human serum with CVF-B in the presence of 0.01 M EDTA converted them to components with higher mobilities on immunoelectrophoresis.

ABO Blood-Group System↗
PubMed1975

Trypsin-activated complex of human factor B with cobra venom factor (CVF), cleaving C3 and C5 and generating a lytic factor for unsensitized guinea pig erythrocytes. II. Physico-chemical characterization of the activated complex.

A complex, CVF-B, between cobra venom factor (CVF) and human factor B(B) showed weak, short-lived enzymatic activity against the third component of human complement (C3). Once activated with trypsin, it showed strong, stable activity against C3 and C5. CVF-B, an activated form of CVF-B complex, was not affected by the trypsin inhibitor, diisopropylfluorophosphate and neuraminidase. Heating at 56 C for 30 min completely destroyed its activity and heating at 50 C for 30 min destroyed approximately half its activity. The activity of DVF-B decrease markedly at pH 6.0 but was stable at pH 6.5 to 8.5. CVF-B lost 90% of its activity on reduction with 1 mM dithiothreitol, and was completely adsorbed on a cellulose acetate membrane. CVF-B was found to be a complex of CVF and glycine-rich gamma-glycoprotein, with a molecular weight of 340,000. The CVF-B molecule consisted of 4-polypeptide chains, 3 of which were derived from CVF and one from GGG. Hemolytically active CVF-B may be formed from 2 molecules with four-polypeptide chains linked by unknown bonds. Human, rat and guinea pig sera could react with CVF-B to generate a lytic factor. Human and sheep erythrocytes were not sensitive to the lytic factor generated by CVF-B, whereas liposomes prepared from their membrane lipids were equally sensitive to the lytic factor.

ABO Blood-Group System↗
PubMedDate not supplied

The major component of Na-CBZ-L-lysine thiobenzyl ester (BLT)-specific proteases in cytoplasmic granules of murine intraepithelial lymphocytes is granzyme A.

Na-CBZ-L-lysine thiobenzyl ester (BLT)-specific proteases in cytoplasmic granules of intraepithelial lymphocytes in the murine intestine (iIEL) were characterized. BLT-specific proteases were isolated with the Sephacryl S-200 column chromatography, and the sample isolated contained a protein with a molecular weight of 58 kDa. The 58 kDa protein consisted of the homodimer of the 30 kDa subunits. The 58 kDa protease was detected by [3H] diisopropylfluorophosphate (DFP)-labeling, and also detectable by the immunoblotting using an antibody against the partial synthetic peptide of granzyme A. The cytoplasmic granules of iIEL were stained positively by an immunofluorescence with anti-granzyme A antibody. Therefore, it was suggested that the major BLT-specific proteases present in cytoplasmic granules of iIEL might be granzyme A.

Animals↗